<!-- index.html -->
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <title>typeof demo</title>
	</head>
  <body>
    <script>
      console.log(typeof "jerry");//"string"
      console.log(typeof 12);//"number"
      console.log(typeof true);//"boolean"
      console.log(typeof undefined);//"undefined"
      console.log(typeof null);//"object"
      console.log(typeof {name: "jerry"});//"object"
      console.log(typeof function(){});//"function"
      console.log(typeof []);//"object"
      console.log(typeof new Date);//"object"
      console.log(typeof /\d/);//"object"
      function Person(){};
      console.log(typeof new Person);//"object"
    </script>
  </body>
</html>
